Trilobitina

Trilobitina is an extinct sub-class of marine arthropods that lived from the Early Cambrian to the Late Devonian periods. They are characterized by their three-lobed body plan, which gives them their name, derived from the Greek words "tri" (three) and "lobos" (lobe). The body of a trilobite is divided into three distinct tagmata: the cephalon (head), the thorax (middle section), and the pygidium (tail). The cephalon typically bears a pair of compound eyes and a pair of antennae. The thorax is segmented and can be flexible, allowing some trilobites to enroll like a pill bug. The pygidium is usually a fused, shield-like structure.

Trilobites were incredibly diverse, with over 20,000 described species. They occupied a wide range of ecological niches, from bottom-dwelling scavengers and predators to free-swimming filter feeders. Their fossilized exoskeletons are common in Paleozoic sedimentary rocks, making them important index fossils for geological dating. The study of trilobites, known as trilobitology, provides valuable insights into ancient marine ecosystems, evolutionary history, and paleogeography. Their demise at the end of the Devonian is one of the major extinction events in Earth's history.